Ring nebula

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Planetary Nebula
Data of the Ring Nebula
Messier 57, the Ring Nebula in the Lyre, captured by the Hubble Space Telescope
Messier 57, the Ring Nebula in the Lyre, captured by the Hubble Space Telescope
Constellation lyre
equinox : J2000.0
Right ascension 18h 53m 35.079s
declination + 33 ° 01 ′ 45.03 ″
Apparent brightness  (visual) +8.8 mag 
Apparent brightness  (B-band) +9.7 mag 
Angular expansion 1.4 ′ × 1 ′  
Central star
Apparent brightness 15 likes 
Physical data
Redshift (−64 ± 2)  ·  10 −6 
Radial velocity −19.2 km / s 
distance 2300 ly
(700 pc ) 
Absolute brightness −0.3 mag 
Dimensions 0.2 M
diameter 0.9 ly
Age 20,000 years
discovery Charles Messier
Date of discovery January 31, 1779
Catalog names
 NGC  6720 •  PK  63 + 13.1 •  GC  4447 •  h  2023 •  M  57

The Ring Nebula (also called Messier 57 or NGC 6720 ) is a planetary nebula in the constellation Lyra .

The nebula is the remnant of a star that shed its outer gas envelope around 20,000 years ago. The gas envelope is expanding at a speed of 19 km / s and currently has an apparent diameter of around 118  arc seconds , which means an absolute diameter of around 1.3 light years at a distance of 2300 light years. In the telescope , the nebula appears ring-shaped, which is why it is often referred to as the ring nebula in the lyre . In fact, the visible gas envelope resembles a torus . In the center of the nebula there is a white dwarf star with a surface temperature of around 70,000 ° C and an apparent brightness of 15.8 mag.

M 57 can be found relatively easily because it is roughly in the middle of the connecting line between the stars β and γ Lyrae .


M 57 was seen by Antoine Darquier in mid-February 1779 during observations along the orbit of comet Bode (C / 1779 A1 (Bode)). For a long time this was considered to be the first observation of the Ring Nebula. In the same year Charles Messier added it to his catalog . According to new sources, however, Messier himself observed the object for the first time on the morning of January 31.

Darquier compared the appearance of the nebula to a planet, which led the astronomer Friedrich Wilhelm Herschel to call this type of nebula a Planetary Nebula .


M57, infrared image from the Spitzer Space Telescope

M 57 can be perceived as a foggy "smoke ring" even in a small telescope from an opening of 10 cm. However, this is relatively small, so that higher magnifications (> 100) are useful. In telescopes with an aperture of 20 cm or more, structures in the ring become visible at higher magnification.

The central star is extremely faint with an apparent brightness of 15.8 m . To observe it, you need a telescope with an opening of at least 25 cm.

Web links

Commons : Ring Nebula  - album with pictures, videos and audio files

Individual evidence

  1. SIMBAD Astronomical Database
  2. a b c d e f g h i Messier 57 at SEDS
  3. cseligman.com
  4. ^ Don Olson, Giovanni Maria Caglieris: Who discovered the Ring Nebula? In: Sky and Telescope , June 2017, pp. 32–37